Outgoing Prime Minister Shinzo Abe was hospitalized Thursday after being diagnosed with a stomach and intestine disorder as well as whole-body fatigue, one of the causes apparently behind his surprise resignation announcement the previous day.

Abe has been plagued by a "functional gastrointestinal disorder," whole-body fatigue and mental stress for more than a month, his physician, Toshifumi Hibi of Keio University Hospital, told a news conference in Tokyo.

According to Hibi, Abe has lost 5 kg during the past several months and has become "badly emaciated," Hibi told reporters.